Conjugated aromatic compounds are important compounds in various fields such as agrochemicals, pharmaceuticals and electronic materials. As the method for manufacturing it, US 2006/0058524 A1 discloses a method comprising conducting a coupling reaction of an aromatic halide compound in the presence of a zero-valent nickel complex catalyst having 2,2′-bipyridine and 1,5-octadiene as ligands and a reducing agent.